121806509 has 8 divisors (see below), whose sum is σ = 133073280. Its totient is φ = 110572000.

The previous prime is 121806499. The next prime is 121806527. The reversal of 121806509 is 905608121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 121806509 - 2²⁰ = 120757933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121806539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209 + ... + 15609.

It is an arithmetic number, because the mean of its divisors is an integer number (16634160).

Almost surely, 2^121806509 is an apocalyptic number.

It is an amenable number.

121806509 is a deficient number, since it is larger than the sum of its proper divisors (11266771).

121806509 is a wasteful number, since it uses less digits than its factorization.

121806509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16131.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 121806509 is about 11036.5986155156. The cubic root of 121806509 is about 495.7052274812.

The spelling of 121806509 in words is "one hundred twenty-one million, eight hundred six thousand, five hundred nine".